Thread: Blood Typing

Here's a blood typing program I wrote on a sick bag on an airplane; it's been giving me mounds of trouble. The latest development is that when I try to print the blood types it doesn't show anything.

Sorry for making your eyes bleed, I'm not really going for efficiency here and I've hackneyed more solutions that I can count.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

char bloody [3] = "O- ";

void get_blood_type() {
    if ((rand() % 1) == 1)
        if ((rand() % 1) == 1)
			bloody [0] = 'A';
	if ((rand() % 1) == 1)
		if ((rand() % 1) == 1)
			bloody [0] = 'B';
	if ((rand() % 1) == 1)
		bloody [0] = '+';
	if ((rand() % 1) == 1)
		if ((rand() % 1) == 1)
			bloody [0] = "AB+";
		if ((rand() % 1) == 1)
			bloody [0] = "AB-";
	return;
}
int verify(char recp [3], char blood [3]) {
	int eval [3];
	if (blood [1] == 'B') {
		eval [0] = 1;
		eval [1] = 1;
	
	if (blood [2] == '+')
		eval [2] = '1';
	else
		eval [2] = '0';
	}
	else {
		if (blood [0] == 'O') {
			eval [0] = 0;
			eval [1] = 0;
		}
		else if (blood [0]  == 'A') {
			eval [0] = 1;
			eval [1] = 0;
		}
		else if (blood [0] == 'B') {
			eval [0] = 0;
			eval [1] = 1;
		}
		if (blood [1] = '+')
			eval [2] = 1;
		else
			eval [2] = 'O';
	}
int rval [3];
		if (recp [1] == 'B') {
			rval [0] = 1;
			rval [1] = 1;
		
		if (recp [2] == '+')
			rval [2] = '1';
			else
				rval [2] = '0';
		}
		else {
			if (recp [0] == 'O') {
				rval [0] = 0;
				rval [1] = 0;
			}
			else if (recp [0]  == 'A') {
				rval [0] = 1;
				rval [1] = 0;
			}
			else if (recp [0] == 'B') {
				rval [0] = 0;
				rval [1] = 1;
			}
			if (recp [1] = '+')
				rval [2] = 1;
			else
				rval [2] = 'O';
		}
		int z = 0;
		for (int i = 0; i == 2; i++)
			if (eval [i] <= rval [i])
				z++;
		if (z == 3)
			return 1;
		return 0;
	}
int main() {
	char answer;
	int answerint;
	char donor [3];
	char recip [3];
	printf ("Hello! I'm going to ask you a few questions about blood typing. Answer lowercase \"y\" or \"n\" for yes\
 or no respectively; answer \"q\" to quit.\n");
	for (;1==1;) {
		get_blood_type();
		for (int i = 0; i == 2; i++) {
			donor [i] = bloody [i];
		}
		get_blood_type();
		for (int i = 0; i == 2; i++) {
			recip [i] = bloody [i];
		}
		printf("Can %s donate to %s?\n", donor, recip);
		scanf("%c", &answer);
		if (answer == 'y')
			answerint = 1;
		if (answer == 'n')
			answerint = 0;
		if (answer == 'q')
			return 0;
		if (answerint == verify(recip, donor))
			printf("Good job! Next question.\n");
		else
			printf("Nope.\n");
	}
}

None of your char strings have enough space to hold AB+ or AB- because you've neglected to account for the required null terminator character.

Well, I was originally gonna have g_b_t return an array of chars, but it refused to accept that, so it was made into a global variable.

Maybe I'd be better off writing this in Lisp... :P